config/environments.rb
has
# Require Rails gems. require 'rubygems' require_gem 'activerecord' require_gem 'actionpack' require_gem 'actionmailer' require_gem 'rails'
Change it to the versions you are using, like
# Require Rails gems. require 'rubygems' require_gem 'activerecord', '<= 1.30' require_gem 'actionpack', '<= 1.1.0' require_gem 'actionmailer', '<= 0.5.0' require_gem 'rails', '<= 0.9.1'